Format & Content

Cloud Product (06_L2) File Format Basics

Cloud (06_L2) Product files are stored in Hierarchical Data Format (HDF). HDF is a multi-object file format for sharing scientific data in multi-platform distributed environments. HDF files should only be accessed through HDF library subroutine and function calls, which can be downloaded from the HDF web site. Each of the parameters listed below is stored as a Scientific Data Set (SDS) within the HDF file.

Scan_Start_Time
Description: International Atomic Time at Start of Scan replicated across the Swath
Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
Valid Range: 0.0 to 3.1558E+9 seconds since 1 January 1993 00:00:00

Note that separate Near Nadir (SZA LE 32) Retrievals are stored in (similar/parallel) SDS's with the string "Nadir" in the SDS name. These generally are more reliable than regular retrievals, since they only contain ONLY data that was retrieved with a less oblique instrument scanner view.

Cloud_Top_Height
Description: Cloud Top Height
Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
Valid Range: 1 to 18,000 m
Notes: The highest retrieved is about 96 hPa which translates to about 55000 ft in a tropical atmosphere. Therefore the retrieval is capped at 96 hPa so 18000 m (or 59,055 ft) as a valid range should be good.

Cloud_Top_Height_Day
Description: Cloud Top Height for daytime scenes
Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
Valid Range: 1 to 18,000 m
Notes: The highest retrieved is about 96 hPa which translates to about 55000 ft in a tropical atmosphere. Therefore the retrieval is capped at 96 hPa so 18000 m (or 59,055 ft) as a valid range should be good.

Cloud_Top_Height_Night
Description: Cloud Top Height for nighttime scenes
Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
Valid Range: 1 to 18,000 m
Notes: The highest retrieved is about 96 hPa which translates to about 55000 ft in a tropical atmosphere. Therefore the retrieval is capped at 96 hPa so 18000 m (or 59,055 ft) as a valid range should be good.

Note that seperate Partly Cloudy Retrievals are stored in (similar/parallel) SDS's with the string "_PCL" in the SDS name. These generally have higher uncertainties than regular cloudy scene retrievals, and data users should use a bit more caution and care with these PCL retrievals.